Device for the production of plastic containers by stretch blow forming using an explosive blowing medium

ABSTRACT

A device for manufacturing containers from a plastic material which can be formed by stretch-blowing with a mold, the internal space of which corresponds to the finished container, which is held by its open end by a receiving portion, wherein lines connected to a metering unit are provided on the receiving portion, a moveable stretching die is guided axially through the receiving portion, and an ignitor is arranged for igniting an explosive gas mixture inside the container, and wherein a heater and cooler are provided.

The invention relates to a device for manufacturing containers from aplastics material which can be formed by stretch-blowing, with a mould,the internal space of which corresponds to the finished container, whichis held by its open end by a receiving portion, wherein lines connectedto a metering unit are provided on the receiving portion, a moveablestretching die is guided through the receiving portion, and an ignitionmeans is arranged in order to ignite an explosive gas mixture inside thecontainer, and wherein heating and cooling means are provided.

A device of the type described hereinabove for manufacturing plasticscontainers, for example bottles from polyethylene terephthalate (PET) isknown from international published document number WO98/06559. These PETbottles are manufactured in that firstly a blank is heated to atemperature suitable for stretch blowing, of approximately 100-120° C.This blank is inserted into a tooling mould corresponding to the shapeof the container, and a stretching pressure of at least 2 bar, normallyof 5-10 bar, is produced. With the aid of an axially, and in generalvertically, moveable stretching die, the blank is stretched axially.Then, a blowing pressure is produced in the blank, which is in theregion of 40 bar. In this way the wall of the blank is pressed againstthe inside wall of the mould, and in this way the container is formed.While the stretching pressure is created by blowing an explosive gasmixture into the blank, for example a mixture of oxyhydrogen gas and aninert gas, the blowing pressure is created by igniting the explosive gasmixture, and this blowing pressure presses the wall of the intermediateform, or respectively the partly pre-formed container, completelyagainst the inside wall of the mould. In this way the PET bottle isproduced. The ignition of the explosive gas mixture is done by a sparkgenerator or an emission, and the explosive gas mixture is a mixture ofan oxidising agent and a component which can be oxidised such as, forexample, hydrogen, methane or the like. In the same process ofstretching and blowing, by achieving a brief increase in temperature,sterilisation of the container to be manufactured is possible, so thistechnique is considered very advantageous.

It has been shown, however, that when converted to technology, thecontainers manufactured with the known device could not be usedindustrially. They could not be manufactured and were not reproduciblewith sufficient quality with respect to shape and volume, and also withrespect to their optical appearance. It was for example, not possible tomanufacture PET bottles with clearly transparent walls. To the extentthat it was not caused intentionally or could be accounted for specificreasons, it was thought that this sometimes unattractive appearance wasdue to unavoidable effects of temperature.

The object of the invention is thus to provide a device of the typedescribed in the introduction, with the aid of which plastics containerswith a better appearance, for example with largely clearly transparentwalls, can be manufactured without large additional expenditure.

This object is solved in accordance with the invention in that, on itsend facing the container, the receiving portion can be engaged in aflowable medium-tight manner with a distribution module, through whichmodule the stretching die is moveably guided in the axial direction,extending the receiving portion, and on which at least one connector forflowable media is fitted, in that the at least one connector forflowable media can be closed for sealing the device-side interior space,and in that ignition means is fitted in the device-side interior space.During the manufacturing process, the receiver is, in one stage, insealed engagement with the distributor module, and in the other stage isdisengaged from the distributor module. In the stretching stage, thestretching die is moveably guided through the distributor module andthereby also axially through the receiving portion.

In the case of one embodiment of the invention, a device-side interiorspace is formed by the parts of the device fitted together, these beingthe distributor module, receiving portion and the container located inthe mould. With this embodiment, a flowable medium is conducted throughthe at least one connector for flowable media into the distributormodule, and through this into the receiving portion and the container.

With another embodiment, the device-side interior space is formed by thesame parts of the device, wherein, however, in addition flowable mediumcan also be supplied through the stretching die to the inside of thecontainer.

In the case of a further embodiment, the device-side interior space isformed only by the container and the receiving portion arranged upon it,when, for example, the distributor module is separated from thereceiving portion and the receiving portion is closed. The stretchingdie is conducted axially through the receiving portion, and saidstretching die can include a supply line. It can, however, also beconfigured to be solid.

Each of the different device-side interior spaces (according to theembodiment) can be closed off in the area of the single connector forflowable media or the plurality of connectors for flowable media. Onlyin a closed device-side interior space does the explosion caused by theignition means arranged externally thereto produce the desiredparameters of a brief high pressure and increased temperature. Clearly,this interior space can be opened up again after the termination of themanufacturing process.

The advantage of the limited device-side interior space is its smallvolume. The volume in the container to be manufactured is then lesscritical. The container, and also preferably the receiving portionsupporting it, are namely removed from the device after the respectivemanufacturing process, in order to be subjected to further processing.The device-side volume which was involved in enclosing the space for theexplosion is, by means of the measures according to the invention, sosmall in relationship to the known device that reaction products, forexample water when oxyhydrogen gas is used, remain in significantlysmaller quantities. It has been established that the clouding of thecontainer walls occurs because when oxyhydrogen gas is used, waterformed in droplets is propelled with considerable kinetic energy fromthe inside onto the walls and there causes changes to the surface whichin the end lead to clouding. With the first explosion, and also in thecase of a continuous process for manufacturing only three to sixcontainers, sufficient reaction product was still not formed in thedevice-side interior space, for example the supply and drainage lines,so there were hardly any water droplets present to cloud the internalwalls of the container. With a longer continuous manufacturing process,because of the large number of successive explosions over time, therewas, however, a large enough amount of reaction product (water) suchthat with each following explosion clouding of the container walls wasunavoidable.

The closing off of a small device-side interior space, which is formedonly from the interior space of the distributor module, the receivingportion and the container itself, in particular does not allow anyaccumulation of the unwanted reaction product (water), in that at leastcontainer itself, and preferably from the container and receivingportion is removed after the explosion, and thereby the accumulatedreaction product as well. Insignificant amounts of reaction producttherefore remain in the remaining device-side interior space which, evenin a continuous manufacturing process, can still be ignored after a longperiod.

By means of this change in the construction technique of the device, itis unexpectedly possible to manufacture, without a large cost increase,plastics containers with a better appearance, in the case of PET bottleshaving largely clearly transparent walls.

The invention is further advantageously configured, in that thereceiving portion is hollow and is provided in its end facing thecontainer with a sealing surface through which the stretching die isconducted moveably in the axial direction extending the receivingportion. The receiving portion is preferably hollow so that thestretching die can be moved through the whole elongately configuredreceiving portion from one of its ends axially to its opposite end. Atthe same time, the receiving portion can be connected to the distributormodule in a flowable medium-tight manner by means of the sealing surfacewhich extends around the space for the stretching die, and is thusannular. It is advantageous when the stretching die is guided throughthis annular sealing surface in a flowable medium-tight manner so thatoptionally a flowable medium, preferably gases, can be forced from thedistributor module through the receiving portion into the container tobe manufactured, without the gases getting outside the device. By meansof the hollow configuration of the receiving portion, not only can thestretching die be guided through into the container and drawn out of itagain, but flowable media can also be conducted between the externalsurface of the stretching die and the internal surface of the receivingportion into the container, and additionally the volume inside thereceiving portion is kept relatively small. In particular, the spaceprovided for the explosion can be limited to the device-side interiorspace described, ensuring that chemical reactions do not place in thesupply lines when reaction products occur.

It is furthermore advantageous according to the invention when theclosing means for sealing off the device-side interior space is anon-return valve. Non-return valves are known per se in many variousconfigurations. A non-return valve can be fitted to each connector ofthe distributor module when the embodiment is selected in which thedistributor module belongs to the device which provides the device-sideinterior space. Another configuration of non-return valve can also beprovided in addition or alternatively on the stretching die, optionallyeven in the stretching die, as will be described hereinafter withreference to a preferred embodiment. The device-side interior space, inthe case of an advantageous embodiment, is formed by the container to bemanufactured and the receiving portion, when this assembly can, forexample, be separated from the distributor module.

It is further advantageous in accordance with the invention when thestretching die is configured hollow and is provided with at least oneoutlet aperture arranged on a stretching die tip, at least one flowablemedium inlet, and with at least one internal channel connecting them,and when preferably in the area of the outlet aperture there is fitted anon-return valve. In the case of the hollow stretching die describedhere, the non-return valve is thus located in the stretching die, andthereby in the area of the outlet aperture. Stretching dies for thestretch blowing process are known per se. The preheated blank isstretched with the aid of the respective stretching die in that itsstretching die tip engages with the base of the blank, and pushes itaway. In the case of the embodiment being considered here, it ispossible to arrange an internal channel in the longitudinal direction ofthe stretching die such that the flowable medium can be pushed from itssupply-side end to the opposite side in the direction towards thestretching die tip, and out of the outlet aperture. With thisembodiment, at least one gas can be transported through the internalchannel in the hollow stretching die into the space inside the containerto be produced, as the flowable medium at the outlet aperture adjacentto the stretching die tip can be brought directly into the volume of thecontainer.

With another embodiment, in addition to the flowable medium inlet withan internal channel in the hollow stretching die described, connectorsfor flowable media can be provided, for example, on the distributormodule, so that different gases can be supplied through different lines.In this embodiment too, it is always ensured that in the supply lines nocombustion, and therefore no chemical reactions, can take place when,for example, the explosive gas is ignited in the volume of the containerto be manufactured.

In a preferred embodiment, before ignition of the explosive gas mixture,the non-return valve in the hollow stretching die is closed. Combustioncannot take place then in the internal channel in the hollow stretchingdie. Because the supply and drainage lines for the flowable medium,preferably for the gases, are closed and separated from the device-sideinterior space before the explosion, the volume for the chemicalreaction, particularly for combustion, is entirely limited to thedevice-side interior space. With smaller amounts of flowable mediainvolved in the combustion, smaller amounts of reaction products alsooccur, so advantageously there is little fear of damaging or affectingthe internal surfaces of the container to be manufactured. In this way,the appearance of the container walls can be considerably improved.Moreover, all the advantages of the known stretch-blowing process can bemade use of, including sterilisation by combustion.

It is further advantageous according to the invention when in the areaof the outlet aperture an ignition means is fitted inside the hollowstretching die on the side of the non-return valve facing away from theoutlet aperture, and preferably is electrically connected via cables orconductor pathways to a control unit. The ignition of the explosivemixture of flowable media can take place almost in the centre of thecontainer to be manufactured, using such a design for the hollowstretching die. Parts of the device set further outside the containercan then be disengaged or closed according to the process. The actuationof the ignition means via the cable or conductive pathway also takesplace advantageously through the hollow configuration of the stretchingdie. The connection of the non-return valve causes no interference, butinstead it is preferably selected such that the whole internal channelin the hollow stretching die can be separated by means of the non-returnvalve from the explosion space, namely by closing the non-return valve.

In a further advantageous configuration of the invention, the hollowstretching die, which is driven such that it is moveable in thelongitudinal direction, is a steel tube with a cap-shaped stretching dietip on which the flowable medium outlet is provided as a hole structure,wherein the non-return valve is provided with a valve body movable withrespect to a sealing seat fitted inside the steel tube, and preferablycarrying turbulence producing means. The hollow stretching die can inpractice be made from a steel tube of stainless steel, the stretchingdie tip of which is nevertheless provided with a cap which isexchangeable, and consequently matching the properties of the respectiveblanks to be formed, as during the process said cap stretches thepre-heated blank by engaging with its base. The flowable medium outletis fitted to the cap-shaped stretching die tip, preferably in the endregion of the steel tube, where the stretching die tip is connected tothe steel tube by means of a screw or another fastening means. As farabove this as possible on the stretching die tip, the flowable mediumoutlet is located. It has a hole structure. This means that at least onehole is arranged in the external wall of the tube such that the gases orother flowable media flowing through the internal channel of the hollowstretching die can exit from the steel tube through this hole orrespectively through a suitable number of holes. It is also possible forthe flowable medium outlet to have a different exit arrangement withregularly or irregularly distributed holes. A hole structure can also beunderstood as a porous body of sintered metal, ceramics or the likewhich can then act at the same time as non-retum protection.

A preferred embodiment of the invention uses a hollow stretching diewith a non-return valve which is also arranged in the area of thestretching die tip, however at a certain distance from it which is usedon the one hand for receiving the flowable medium outlet, and on theother hand for the ignition means. The non-return valve in thisembodiment has a valve body which can be moved with respect to a sealingseat inside the steel tube such that in this way the non-return valve isclosed. If such a stretching die is arranged with strongly verticalcomponents, preferably completely vertically, in the device according tothe invention, the valve body exerts, by means of its weight, a kind ofspring tensioning downwards against the sealing seat, so without aflowable medium flowing out of the internal channel, because of itsweight the valve body always falls down onto the sealing seat andthereby closes the non-return valve. Obviously, the closing of thenon-return valve can also be obtained in some way by building in aspring, which is necessary in particular when there is a non-verticalarrangement of the stretching die. Ignition takes place in any case inthe device-side interior space, that is to say in the upper remainingspace in the steel tube adjacent to the flowable medium outlet andoutside the stretching die in the volume of the container, so the gaspressure increased by the explosion additionally presses the valve bodyagainst the sealing seat and closes the non-return valve.

The valve body can preferably carry turbulence-producing means. In thisway a better turbulence of the flowable media mixture is obtained whenit leaves the stretching die. For example, the moveable valve body canbe provided with flowable medium guides running in a spiral shape on itsexternal surface. Alternatively, outlet holes can be bored diagonally inthe stretching die in order to give the exiting flowable medium atangential speed component.

In the steel tube of the hollow stretching die, in other embodiments oralternatively in addition to the measures in the context of theembodiments described hereinabove, means are provided for good mixing ofthe flowable media. Thus, Christmas-tree-shaped components provided withlateral paddles can be provided in the hollow stretching die in order toimprove turbulence of the flowable media while they are being conductedthrough.

The cap-shaped stretching die tip can be manufactured from differentmaterials, wherein it can be made of solid plastics, of aplastics-coated steel cap, or of ceramics. A device has also alreadybeen operated and evaluated in which the stretching die tip is composedof steel. The reason for using steel instead of plastics, and fortesting it, is to avoid excessive heating, and therefore affecting ofthe external surface of the stretching die in continuous operation.

It is advantageous according to the invention when the receiving portionis driven moveable perpendicularly to its longitudinal central axis. Inthis way it is unexpectedly possible to transport away a large part ofthe device-side interior space, namely the space in the hollow receivingportion, after each stretching and blowing process, that is to say inparticular after each combustion, together with the reaction productsadhering to the walls, from the remaining stationary device, forexample, the distributor module with the hollow piston. All thesereaction products take no part in the subsequent process of stretchingand blowing, and in particular in the chemical process of combustion.The device-side interior space, which can nevertheless be coated withreaction products, is then limited to the space in the upper stretchingdie and in the distributor module. When an oxyhydrogen gas is used, solittle water is taken along as a reaction product to the followingcombustion process, that affecting of the internal container wallsduring and after the explosion is not a risk.

Furthermore, a preferred embodiment of the invention is characterised inthat the receiving portion is widened at the end facing the distributormodule to form a service space in which, preferably, a centering isplaced. The respective container to be manufactured has, in the case ofa PET bottle, on one long end the infilling and respectively pouringaperture in the form of a band with an external thread. In the case ofthe known device, the receiving portion grips around this open end ofthe container. Also according to the invention, the container to bemanufactured is retained most practically at its open end which ispreferably in the form of a band with an external thread. The filling ofa sterilised container is done through this infilling and respectivelypouring aperture, which can also generally be described as a closure. Inorder that the sterile contents does not come into contact withgerm-laden surfaces externally or internally on the closure, it would beadvantageous when not only the inside of the container is sterilisedduring the combustion process in the process according to the invention,but the upper annular edge on the end face, and if possible even thethread are sterile on the outside. If according to the teaching of theinvention the receiving portion is widened at the end where thecontainer is received, there is formed an albeit small additional volumefor the gas involved in the combustion, which adjoins the surface of theexternal thread and sterilises it during the blowing process.

It is also preferred when in this widened service space there is fitteda centring, as then both the blank and the future container can be wellcentred and retained. Although the centring is an additional part, whichpartially fills the service space, the contact with the sterilisinggases during and after the combustion is not hindered or affected by it,particularly as an edge flange additionally acts as a retainer.

It is further advantageous according to the invention when in thepreferably stationary distributor module a hollow piston, driven axiallymoveable relative to said module, is provided, which has on its externalend opposite the receiving portion an annular opposing sealing surfacefitting the receiving portion. The distributor module can be alsoconstructed in one piece, and connected in a sealing manner with acorrespondingly moved receiving portion such that this connectionbetween the receiving portion and distributor module can be terminatedin a controlled manner. The termination is, however, done by means ofthe existing measures particularly advantageously with the hollowpiston. In order to connect the distributor module to the receivingportion, and respectively to disconnect it, neither the distributormodule nor the receiving portion needs to be moved axially—approximatelyin the direction of the hollow stretching die—as the hollow piston isdriven axially moveably, preferably pneumatically. On its external end,the hollow piston carries an opposing scaling surface fitting thereceiving portion, which surface comes into sealing engagement with thesealing surface of the receiving portion when the receiving portion isconnected to the distributor module. After the blowing and sterilisingprocess, the movement of the hollow piston is reversed, so the sealingsurface is disengaged from the opposing sealing surface, and then thereceiving portion can be displaced in die manner described hereinaboveperpendicularly to the direction of its longitudinal axis. Thisdisplacement transportation takes place each time following ablowing-sterilising procedure in the step-wise operating manufacturingprocess. According to the invention, in the distributor module, forguiding the stretching die, a sealing passage can be fitted in alignmentwith the hollow piston. With this, the movement of the stretching die inthe axial direction through the distributor module, the hollow pistonhereof, the receiving portion connected thereafter, and into thecontainer, and respectively out of these parts, takes place whether thedevice-side interior space remains closed off in a gas-tight manner.

According to the paths of the flowable medium through the stretchingdie, past it or both of these, it can be advantageous when according tothe invention at least one supply and connected to the metering device,and a drainage line, is connected to the distributor module. Thedrainage line serves to remove the reaction products, for example of thecombustion gases, and optionally flowable residues.

The supply line is connected to the metering unit, which will bedescribed hereinafter in more detail with reference to a preferredembodiment. There can be supplied, for example, for oxyhydrogen gas,hydrogen through one supply line and a mixture of oxygen and an inertgas through another supply line. With this it is advantageous when aflowable rinsing agent is forced from a further supply line to drive thereaction products out of the drainage line.

It should be noted that pressure sensors and temperature measuringdevices could be arranged at different places in the device, preferablyin the area of the distributor module, but also in the hollow stretchingdie.

It is also clear, that the ignition means can work on different physicalprinciples. The ignition of the mixture of media takes placeelectrically in the most simple case by means of a spark discharge, madefor example by a spark plug which can be fitted on the stretching die oron the distributor; or by means of static discharge. Other ignitionmethods are conceivable, for example by beaming electromagnetic energy,in the form of a laser, high frequency or microwave pulse, or with theaid of a catalytic procedure.

Another advantageous embodiment of a metering unit provides the mixingof different flowable media directly in front of the stretching die,with directly following introduction into the blank. Particularly fromthe safety aspect, this represents a good compromise between themanufacturing of the mixture in a separate, explosion protectedpressurised container and the metering unit described hereinabove, inwhich by means of metering cylinders individual flowable media and/ormixtures of flowable media are supplied to the device-side interiorspace.

A practical embodiment is further characterised according to theinvention in that in each of the supply and drainage lines connected tothe distributor module there is connected a non-return valve, and theignition means is housed in the distributor module. The stretching dieis then surrounded by the space in the distributor module, the spacebetween the stretching die and hollow piston and that between thestretching die and receiving portion with a gap. This gap means anannular space which can be seen as a channel for flowable media and canbe set out accordingly. When set out larger, larger quantities offlowable media can be pumped into the container, and vice-versa. Theexplosion triggered by the ignition means in the distributor module thenpropagates itself very rapidly into the entire space filled withflowable medium. This space is limited by the non-return valves on thelines to the distributor module.

In an advantageous further configuration of the invention the hollowpiston has on its end facing the receiving portion an annular sealingseat, and the stretching die carries on its end which is moveable intothe container to be manufactured a radially widened portionperpendicular to its longitudinal axis for engaging with the sealingseat. This can be ball, cone or ring-shaped or the like. In thisembodiment the stretching die is solid and can be configured with asmaller diameter with the result that a greater flow channel isavailable for the flowable medium outside the stretching die. Thisencourages a rapid, brief manufacturing process. The space provided forthe explosion is closed off by withdrawing the stretching die andthereby introducing the widened portion into the sealing seat withoutthe necessity for further non-return valves, wherein then the ignitionmeans simply has to be arranged in the area of the receiving portion.

Another radial widened portion of the stretching die is also conceivablein its central area, wherein when there it is better to describe it as astep. This widened portion can then also close off the space for theexplosion by engaging with the sealing seat on the hollow piston, whilethe stretching die still remains in the extended stretching position. Inthis way, the process time can be further reduced, as the stretching diedoes not have to be firstly withdrawn from the container before theexplosion can be triggered.

It can be advantageous when according to the invention the cooling meansdescribed in the introduction are used to separately cool the stretchingdie. This can indeed reach a temperature of 100° C. or more even afterseveral steps in the step-wise continuous operation, so the materials ofthe device are subjected to a high degree of stress. It is thenadvantageous to limit the temperature of the moveable stretching die,and this can be done well, despite repeated explosions, by providingsuitable cooling means.

Although the internal channel of the hollow stretching die waspreviously described as a supply line, clearly the supply of the mixturecan also be via the distributor module and the removal of the reactionproducts correspondingly via the stretching die.

Further advantages, features and possibilities for application of thepresent invention will be evident from the following description incombination with the attached drawings, which show preferredembodiments. There is shown, in:

FIG. 1 in section, the transporting of blanks and completed blowncontainers by means of a distributor,

FIG. 2 a diagram of the development of pressure over time in the blank,and respectively the container to be manufactured,

FIG. 3a the left-hand half of a first embodiment of a metering unit,which continues to the right with the lines interrupted,

FIG. 3b the right-hand half of the metering unit of FIG. 3b, that is tosay the continuation of the lines from the left, with the stretch-blowncontainer above right,

FIG. 3c the left-hand half of a second embodiment of a metering unitwhich also continues to the right with the lines interrupted,

FIG. 3d the right-hand half of the metering unit of FIG. 3c analogous tothat of FIG. 3b;

FIG. 4 in an enlarged scale, the upper and respectively container-sideend of the hollow stretching die,

FIG. 5 the same end of the stretching die as in FIG. 4, shown incross-section, in this case in perspective,

FIG. 6 an operating state of the device, in which compared to FIG. 1 thedistributor arranged in the centre at the bottom is connected in asealing manner to the receiving portion, wherein the container ispre-stretched and formed,

FIG. 7 another state of the stretching-blowing process, in which formingis done by explosion,

FIG. 8 the same step of the process as in FIG. 7, however in perspectiveand partially cut away,

FIG. 9 with another embodiment, a similar process step as in FIG. 6,wherein however the pre-stretching and forming is done by a differentlyconfigured stretching die,

FIG. 10 the same embodiment as in FIG. 9, but with forming by explosion,

FIG. 11 a similar illustration of the device as in FIGS. 7 and 10,wherein a different type of stretching die is used, and

FIG. 12 enlarged, in cross-section, the receiving portion wit thecentering fitted above, by means of which the container to bemanufactured is supported.

FIG. 1 shows cut-away at the top right a container 1 manufactured by thestretch-blowing process made from plastics, for example, PET. While thecompleted container formed and removed from the tool is labelled 1, thecontainer partly pre-formed by stretching and blowing is labelled 1′ inthe following drawings. The container 1 is manufactured from a blanklabelled 2. Only the parts of the entire manufacturing unit which areimportant for the invention are shown, while parts of the tool known perse are omitted, thus, for example, the mould, the interior space ofwhich corresponds to the finished container 1. The retainers and railsfor transporting the workpieces according to the arrow 3 into theprocessing station and out of it are also omitted in the drawing. Thereceiving portion 4 is shown, however, which is widened at the upper endto form a service space 5, in which a centring 6 is fitted.

The container 1 to be manufactured is in this case shown as a PETbottle, which is arranged with its open end 7 upside down, facingdownwards, and supported in the centring 7 and retained in a sealingmanner in the receiving portion 4.

On the receiving portion 4 lines are provided axially, later describedin more detail according to the embodiment, which can be connected tothe receiving portion 4 and are removable from it such that thereceiving portion is freely moveable with respect to the lines and thetool parts carrying them. These lines are in turn connected to ametering unit described in more detail in FIGS. 3a and 3 b. In FIG. 1,the lines 9 and 10 are shown, the connection of which to the meteringunit is shown in FIG. 3b. It is clear that depending on the placeselected for producing the mixture—the metering unit, distributor moduleor blank—the distributor module can include several supply lines 10, 10′instead of a single supply line 10. A pressure sensor 8 in thedistributor module can be used for process control. The second supplyline 10′a and third supply line 10′b (the further supply lines 10′) arebehind the pressure sensor 8 in FIG. 3b.

For blowing and stretching the blank in the blown intermediate stage orrespectively the intermediate forming stage (for example, in FIG. 12) ina manner known per se, a stretching die generally labelled 11 is used,which is guided axially moveably through the receiving portion 4.Additionally according to the embodiment of the device, in one place anignition means 12 is arranged for igniting an explosive gas mixtureinside the container 1′. Heating and cooling devices, including thecooling means for the stretching die 11 are omitted for simplificationand increasing the clarity of the drawings.

In the Figures of the embodiments shown here, many parts of the device,for example also the stretching die 11, extend in a vertical directionfrom below to above or vice-versa, wherein the construction andfunctioning of the device are simplified when the container to bemanufactured is arranged above, the receiving portion 4 in between, andthe stationary tool parts below. In the direction of the longitudinalcentral axis 13 shown in broken lines in FIG. 4, the stretching die 11also extends in the vertical with which the longitudinal central axis 13should be thought of as coinciding. This longitudinal central axis alsoruns centrally through the receiving portion 4 and the blank 2 orrespectively the future intermediately formed container 1′ and thecompleted container 1. When the respective receiving portion 4 ismoveable in the direction at right-angles to the longitudinal centralaxis 13, to transport the blanks 2 or respectively the containers 1,this transport direction is in the horizontal direction according to thearrow 3, while the longitudinal central axis is vertical.

The receiving portion 4 can be brought into engagement by its end facingthe container 1 or respectively the blank 2, which is always fittedabove, in a flowable medium-tight manner with a distributor module 14.This distributor module 14 is stationary and has a continuous verticalbore 15. At the bottom of this there is located a sealing passage 16through which the stretching die is moveably guided concentrically andin a sealing manner from the outside into the distributor module andoscillating upwards and downwards. At a small distance above the sealingpassage 16 in the inside of the distributor module 14, preferably at adistance of between 2 and 20 mm, there is located a hollow piston 17which is movably driven relative to the stationary distributor module 14axially in the bore 15 described, and thus parallel to the longitudinalcentral axis 13. At a distance from the internal walls of the hollowpiston 17, the stretching die 11 moveable with respect to the partsdescribed runs, which can penetrate axially in alignment with thereceiving portion into said receiving portion, and also into the blank 2or respectively the container 1 held by it.

The hollow piston 17 has on its upper, namely its outer, end 18 whichfaces the receiving portion 4, an annular opposing sealing surface 18fitting said receiving portion. The hollow receiving portion 4 has onits end (below) facing the container 1 or respectively the blank 2, anannular sealing surface 19. This matches the opposing sealing surface 18of the hollow piston 17 in such a manner that when the hollow piston 17moves out of the position shown in FIG. 1 upwards towards the receivingportion 4, the opposing sealing surface 18 goes into the sealing surface19, and ensures a suitable, flowable medium-tight connection. In otherwords, by means of the sealing surface 19 at the bottom on the receivingportion 4 and the opposing sealing surface 18 above on the hollow piston17, the receiving portion 4 can be brought into flowable medium-tightengagement with the distributor module 14. By means of the hollow spaceformed by the hollow receiving portion 4 and the hollow piston 17, thestretching die 11 is introduced axially such that the longitudinalcentral axis is common to all the parts of the tool.

Already in FIG. 1, and particularly clearly in FIGS. 4 and 5, a hole 20is shown in the stretching die 11, which is one of the connectors forflowable media, which are connected via the stationary distributormodule 14. In one embodiment, a connector for flowable media is theaccess 21 to the stretching die 11 which is then configured hollow; orwith another embodiment, connectors for flowable media are labelled 9 or10 on the distributor module. On each connector for flowable media,non-return valves 23 are fitted for closing off and sealing thedevice-side interior space 22. According to the embodiment, these canhave widely differing configurations, as will be explained in parthereinafter. The device-side interior space 22 is the space in the tooland in the blank 2 or respectively the container 1, in which theexplosion of the gas mixture takes place.

The actual process with the ignition of the explosive gas mixture, inthe embodiment selected here, a gas mixture, is well explained withreference to FIG. 2. Over the time t (in ms) the pressure (in bar) isapplied in the device-side interior space 22. The dashed line shows theconventional process. At t=0, a mixture of hydrogen, oxygen and inertgas is blown in through the connectors for flowable media 9, 10, 21provided for the purpose, as shown approximately in FIGS. 6 and 9, whilethe stretching die 11 is pushed out of the distributor module 14 throughthe receiving portion 4 upwards through into the blank such that it isstretched into the intermediate form of the intermediate container 1′shown rounded. Clearly, the blank 2 is previously heated to preferably120° C. Between the times t₁ and t₂, the internal pressure is kept inthe range of approximately 5-10 bar (stretching pressure), so that thehot blank 2 is stretched and thereby its diameter also increases.Formerly, at time t₂ the internal pressure of the non-explosive gaseswas increased to a good 30 bar, and kept until time t₅, whereby theblank 2 or respectively the intermediately formed container 1′ wascompletely pressed against the tool mould, and thereby obtaining thefinal form of the container 1 to be manufactured, for example, the PETbottle. Ventilation then took place, the mould was meanwhile cooled, andthe finished container removed from the form after time t₇.

With the new process with the explosive mixture, for example,oxyhydrogen gas, the stretching and blowing takes place by means of theincreased internal pressure up until time t₂ in the same way.Thereafter, however, the oxyhydrogen gas is ignited, whereby thepressure is briefly increased up to time t₃ to over 35 bar, and up totime t₄ goes down again to below 20 bar. An inert gas or another gasphysically involved with the mixture but not involved in the chemicalreaction is introduced at pressure between times t₄ and t₆ into theinterior space 22 and respectively kept there under pressure in order tohold the internal walls of the container 1 just manufactured against theinternal wall of the mould, and to ensure cooling and hardening of theplastics material. After time t₄ depressurisation takes place and at t₇,the container 1 can be removed from the tool.

A first embodiment of the metering unit is described with reference toFIGS. 3a and 3 b. The distributor module shown in FIG. 3b on the rightis, in the case of the embodiment shown here, supplied with a gasmixture via the supply line 10′a or the supply line 10′b. This can bedone via the respective non-return valve 23 and the respective valvelabelled 24 via the line 8′ or the line 8″ from a mixing andpressurising cylinder 25 (FIG. 3a). The latter is driven by the motor Mand can mix various gases according to the setting of the valves 24, andsupply the further supply line 10′ by means of the line 10′a and/or10′b. With the preferred embodiment taken here, the gas container 26holds a mixture of argon and oxygen (alternatively with anotherembodiment, for example, also air). The gas container 27 contains argon.By means of the mixing and pressurising cylinder 25, which can have, forexample, a volume of 2 litres, oxygen can be mixed as desired with amore or less large amount of argon, and then supplied to the supply line8.

In order for oxyhydrogen gas to be an explosive gas mixture, accordingto FIGS. 3a and 3 b oxygen is stored in the gas container 28. This ispre-compressed by means of a pressurising cylinder 29 with a volume of,for example 0.8 litres, to a first pressure of 2.5 bar, and to astretching pressure of 10 bar. For safety reasons, further non-returnvalves 23 are connected in front of the connector for flowable media 21in the stretching die 11.

Alternatively, in order to avoid the storage of large quantities ofoxygen, and thereby to further increase the safety of the installation,the oxygen required can, for example also be continuously produced inthe respective small amounts required in a parallel manner in anelectrolysing unit.

By means of the supply line 9 connected to the metering unit, a flushinggas is introduced through the line 30 in the direction of the arrow 31shown at the bottom right in FIG. 3b, again by means of a non-returnvalve 23, into the distributor module 14. This flushing gas is, withthis embodiment, compressed air, and acts to force out water and gasresidues from the system after the explosion.

In FIG. 3b at the bottom right the zig-zag arrow in the circle is thesymbol for high voltage generation 32. The high voltage then leads intothe ignition means 12 lying further up, to ignite the explosion.

FIGS. 3c and 3 d describe a second other embodiment of a metering unit.The metering unit according to FIGS. 3c and 3 d is constructed in a verysimilar manner to that according to FIGS. 3a and 3 b, so like parts havelike terms and reference labels. The pressure tank 25 a shown in FIG. 3cis different, from which tank only one supply line 8′ leads via thevalve 24 to the non-return valve 23 and from there as a supply line 10′ato the distributor 14.

The first embodiment according to FIGS. 3a and 3 b can be modified toobtain the embodiment according to FIGS. 3c and 3 d such that when blankpressing takes place at under 10 bar, the mixing and pressurisingcylinder 25 with its supply and drainage lines is replaced by thepressure tank 25 a described. In said tank the gases are mixed, forexample, the gases coming from the gas containers 26 (argon and oxygen)and 27 (argon) and fed to the pressure tank 25 a. From this pressuretank 25 a, there is then only one supply line 8′ leading to thedistributor module 14, as is shown in FIG. 3d. Instead of the mixing andpressurising cylinder 25 of FIG. 3a, in the second embodiment of FIG.3c, oxygen can be mixed as desired with a more or less large amount ofargon in the pressure cylinder 25 a, and then supplied to thedistributor via the supply line 10′a.

In FIGS. 4 and 5 the upper or respectively the container-side end of thehollow configured stretching die 11. Right at the top there is located astretching die tip 33 made from plastics, which in other embodiments canalso be composed of steel or ceramics. In the present embodiment,plastics is selected so that the tip used for the stretching of thecontainer 1′ does not heat up excessively. By means of the continuingand discontinuously operating ignition means 12, the stretching die 11heats up, which stretching die is, in its substantial portion below thecap-shaped stretching die tip 33, a steel tube 34. The stretching dietip 33 is screwed via the holder 35 to the steel tube 34. At a smalldistance below the holder 35, holes 20 are located in the steel tube 34,which serve as outlets for flowable media in a hole structure. Theflowable medium has to be able to leave the elongated device-sideinterior space 22 from the hollow stretching die 11, through the holes20. The device-side interior space 22 is, in the case of thisembodiment, an elongated internal channel which extends parallel to thelongitudinal central axis 13, from the non-return valve 23 to the heightof the holes 20.

The ignition means 12 has, in the illustration according to FIGS. 4 and5, a spark plug which is also parallel to the longitudinal central axis13, and terminates upwardly in the area of the holes 20. The non-returnvalve 23 is connected below. The ignition device 12 is thus arrangedabove with respect to the non-return valve 23, that is to say on theside facing the holes 20. On the side of the non-return valve 23opposite the holes 20, a cable 36 is connected which is fed from thenon-return valve 23 parallel to the longitudinal central axis 13downwards, as can be seen clearly in FIG. 5. This cable 36 iselectrically connected to a control unit which is not shown, in order tobe able to ignite the explosion at any time desired.

The non-return valve 23 in the hollow stretching die 11 is provided witha moveable valve body 37. This valve body 37 can be set up to beflowable medium-tight against a stationary sealing seat 38 fittedinternally in the steel tube 34. It is evident from FIGS. 4 and 5 thatwith ignition of a gas mixture in the device-side interior space 22(above the internal channel 39 described in the hollow stretching die11) the over-pressure presses the valve body 37 vertically upwardsagainst the sealing seat 38, and thereby triggers the functioning of thenon-return valve 23.

With the embodiments shown here, the valve body 37 can carry turbulenceproducing means, for example, turbulence producing paddles like thebranches of a Christmas tree, or alternatively gas outlets arranged in aspiral shape. In this way the turbulence of the gas mixture when leavingthe stretching die 11 can be further improved.

While in FIG. 1, the distributor is shown separated from the receivingportion, so that the receiving portion 4 can be moved perpendicularly tothe longitudinal central axis 13, namely in the direction of the arrow 3(horizontally) from one station (left) to the next (centre or right)relative to the distributor 14, in FIG. 6 the connection of thedistributor 14 and respectively its hollow piston 17 with the receivingportion 4 is shown. FIG. 6 shows a specific operating condition. Inorder to produce this gas-tight connection between the receiving portion4 and the distributor 14 and respectively its hollow piston 17, thehollow piston 17 is moveable up and down vertically in the direction ofthe longitudinal central axis. The receiving portion 4 is not moveablein this direction, and the distributor 14 is in any case stationary. Ifcompressed air is fed via the lower pneumatic connector 40 into thecylinder within the continuous vertical bore 15, the hollow piston 17then moves upwards into the position shown in FIG. 6. (The other wayaround, compressed air can be fed into the upper pneumatic connector 40in order to move the hollow piston 17 back down again into the positionshown in FIG. 1).

In order to obtain the operating state shown in FIG. 6, a mixture ofargon as the inert gas, plus oxygen from the gas container 26 is fedthrough the supply line 8 into the space around the stretching die 11,and forced into the space still present as a (heated) blank, as thefluid arrows 41 in FIG. 6 show. During this blowing out, the stretchingdie 11 is also pressed vertically upwards against the base of the blank2 such that the internal pressure plus the mechanical pressure of thestretching die 11 blow out the softened plastics material of the blankinto the intermediate form of the container 1′ according to FIG. 6. Thesupply of oxygen gas helps to support this, which gas is supplied viathe connector for flowable media 21 below in the stretching die 11, andis forced through the internal channel 39 (shown in FIGS. 4 and 5)upwards to the holes 20, where the oxygen flows according to the oxygenarrows 42 into the volume of the intermediate container 1′. The materialof the blank 2 lies, in the form of the intermediate container 1′, moreor less on the internal surface, which is not shown, of the mouldingtool, wherein with the aid of the gases (41, 42) and of the stretchingdie 11, blowing and stretching takes place.

Naturally, it is also possible to force the mixture of inert gas andoxygen in the direction of the further arrow 43 (gas mixture inlet)through the supply line 9 into the distributor module 14, so that itenters in the manner of the fluid arrows 41 in the same way as describedhereinabove into the volume to be blown out. This constituted thepre-stretching and forming.

The next operating state can be well explained with reference to FIG. 7.Here, forming takes place by means of explosion. Behind the holes 20 inthe hollow stretching die 11, there is located the ignition means 12which obtains the signal for ignition by means of its cable 36, when thepre-stretching and forming is finished and the intermediate shape of thecontainer 1′ is obtained. By means of the ignition which is indicated inFIG. 7 at the top by the asymmetrical star 44 (ignition), water isformed from the gas mixture of oxygen and hydrogen by means of theoxyhydrogen gas explosion, according to the formula 2H₂+O=2H₂O.According to FIG. 2, in time t₂ to time t₃ a very high pressure of over35 bar is briefly created. This gas pressure ensures the contact of thestill warm plastics walls on the internal surface of the mould, so theshape of the finished container 1 occurs, as is shown in FIG. 7. In thisstate, the stretching die 11 is located in its position pushed outupwardly. In this position, the holes 20 with the ignition means 12located behind them, lie clearly in the centre in the volume of thecontainer 1 to be formed. Not only does the pressure ensure good formingof the container 1, but also a brief increase in temperature occurs sothat the interior space of the container 1 is sterilised at the sametime.

In order that the configurations and dimensions can be better evaluated,the same illustrations in FIG. 8 are shown in perspective and partly cutaway. In order that water occurring in the device-side interior space 22die to the oxyhydrogen gas explosion can be ventilated and removed, theline 10 leading outwards diagonally downwards is provided, which lineleads to the outlet 45 according to the arrow in FIG. 3b. Additionally,the flushing gas from the line 30 via the supply line 9 for driving outwater and other gas residues can act in a supporting manner.

It is obvious that to obtain lower operating costs it is advantageousnot to simply blow off the argon not involved in the chemical reactionafter forming of the container, but rather to clean and dry it in arecovery installation and use it again.

It can be imagined from FIG. 8 that the hollow piston 17 is moved in thedirection of the longitudinal central axis 13 vertically downwards afterventilation, so that the annular sealing surface 19 on the receivingportion below the opposing sealing surface 18 on the external end of thehollow piston 17 is lifted up such that the state according to FIG. 1 isobtained again. Now, with the aid of the horizontal feed mechanism,which is not shown, the receiving portion 4 is moved with the newlyformed container 1 in the direction of the arrow 3 horizontally out ofthe central position into the position shown in FIG. 8 at the top rightrear. At the same time the receiving portion 4 shown at the left frontis brought with the blank 2 into the central position, so that the stateshown in FIG. 1 is obtained again.

Another embodiment is shown in FIG. 9. Here, the stretching die 11 isnot configured hollow, but instead solid. On its upper, external, freeend, it is provided with a ball 46. For pre-stretching and forming inFIG. 9, inert gas, oxygen and in this case also hydrogen is blown in asimilar manner to FIG. 6, from below from the open end 7 of thecontainer 1′ around the stretching die 11 within the hollow piston 17and the receiving portion 4, vertically upwards from a supply line herelabelled 10, and in accordance with the fluid arrows 41 into the hotblank 2 such that with the aid of the stretching die 11 with its ball 46(located on the tip), the intermediate form of the container 1′ isformed.

In the embodiment of FIG. 9, the non-return valves 23 are active inclosing off the entire device-side interior space as far as inside thedistributor module 14 from the outside. Then, the ignition means 12fitted in the distributor module 14 in the case of this embodiment,which for example could be arranged in the place of the supply linelabelled 8, can explode the oxyhydrogen gas mixture in the wholedevice-side interior space 22, from the distributor module 14 at thebottom to above in the space of the container 1′ still in itsintermediate form. The pre-stretching and forming is also shown in FIG.9.

Another, similar embodiment is shown in FIG. 10, which is constructed ina manner similar to FIG. 9, wherein, however, the ignition means 12 isarranged above and in the area of the opposing sealing surface 18 of theexternal end of the hollow piston 17. The explosion symbolised by theignition star 44 is triggered when the stretching die 11 is located inits lower, withdrawn position. The external sealing surface of the ball46 is then engaged with a sealing seat 47 in the hollow piston. Thedevice-side interior space 22 is located in the case of this embodimentpractically only in the area of the receiving portion 4, and the ball 46with the sealing seat 47 in the hollow piston 17 acts as a non-returnvalve 23.

In FIG. 9, although the sealing seat 47 in the hollow piston 17 is alsoshown at the top, in the case of FIG. 9, the ignition means must then beremoved from the area of the distributor module 14 and taken upwardsinto the area of the receiving portion 4.

Another further embodiment is shown in FIG. 11. Again, the hollow piston17 is provided on its end facing the receiving portion 4 with a sealingseat 48, which has a similar function to the sealing seat 47 in thehollow piston 17 in the embodiment according to FIGS. 9 and 10. In FIGS.9 and 10 this annular sealing seat 47, which tapers vertically upwardsin the manner of a truncated cone, engages with the radially widenedportion, that is to say the ball 46, which can also be configured as acone, ring or the like. The ball 46 was fitted wholly on the free upperend of the stretching die 11 in accordance with FIGS. 9 and 10.

In the embodiment of FIG. 11, on the other hand, the annular sealingseat 48 in the hollow piston 17, which tapers vertically upwards in themanner of a truncated cone, engages with a shoulder 49 on the solidlyconfigured stretching die 11. This shoulder 49 is located far below thefree upper end of the stretching die. The distance from the upper freeend of the stretching die 11 is approximately the same as the length ofthe container 1 to be manufactured plus the length of the receivingportion 4, both measured in the direction of the longitudinal centralaxis 13. The stretching die 11 thus engages by means of its shoulder 49with the annular sealing seat 48 in the hollow piston 17 according toFIG. 11, when the thinner part of the stretching die 11 is pushed upabove the shoulder 49 completely up into the container 1 to bemanufactured. The shoulder 49 can then lie on the sealing seat 48 andcloses off the device-side interior space 22 which constitutes thevolume in the receiving portion 4 plus the volume in the container 1 tobe manufactured from the outside. The annular space in the hollowcylinder 17 and in the distributor module 14 outside the lower, thickerpart of the stretching die 11 with the larger diameter is not subjectedto the high pressure and the high temperature when the oxyhydrogen gasis ignited. The advantage of the embodiment of FIG. 11 compared to thatof FIG. 10 is in that the ignition by an ignition means not shown inFIG. 11, which is arranged, for example, in the area of the receivingportion, can trigger the explosion while the stretching die 11 is stillconducted into its pushed forward “stretching position”. The time takenfor withdrawing the stretching die 11 vertically downwards is thussaved.

In the two embodiments according to FIGS. 9 and 10 on the one hand andalso according to FIG. 11 on the other hand, the stretching die 11 issolid, that is to say is not configured hollow. In both embodiments thedevice-side interior space 22 can be closed off from the outside bymeans of the radially widened portion (ball 46 or shoulder 49), withouta non-return valve having to be arranged in addition.

The further advantage of the embodiment according to FIGS. 9 and 10 isin that the diameter of the stretching die 11 compared to the stretchingdie with the hollow configuration can be very small, with the resultthat a larger free cross-section in the form of the annular space aroundthe stretching die 11 is available for the blowing in of fluid (gasmixtures). In this way time is gained, as the device-side interior space22 can be filled more rapidly with the desired fluid. It is alsoadvantageous that the stretching die 11 in the embodiment according toFIGS. 9 and 10 is no so hot as only a smaller part thereof is located inthe explosion area.

FIG. 12 clearly shows the external thread of the open end 7 of thecontainer 1′ which can later be closed after filling by means of a cap.It is often desired to keep the cap, and in particular its internalarea, including the thread, sterile. It is then advantageous when theexternal thread on the open end 7 of the container 1′ is sterilised.This sterilising is done by brief heating during the explosion of theoxyhydrogen gas, wherein sterilising hot gas also acts in the servicespace 5 within the centring 6 upon the external thread on the open end 7of the container 1′. With suitable size and construction of the servicespace, it is thus also possible to sterilise the closure later used toclose the container in the same operating process.

List of Designations

1 container

1′ partly formed container or respectively intermediate blank

2 blank

3 arrow

4 receiving portion

5 service space

6 centring

7 open end of the container

8 pressure sensor

8′, 8″ supply line

9 supply line

10, 10′ 10 a, 10′b supply lines

11 stretching die

12 ignition means

13 longitudinal central axis

14 distributor module

15 continuous vertical bore

16 sealing passage

17 hollow piston

18 opposing sealing surface

19 annular sealing surface

20 hole

21 connector for flowable media

22 device-side interior space

23 non-return valve

24 valve

25 mixing and pressurising cylinder

26 gas container

27 gas container (argon)

28 gas container (hydrogen)

29 pressure cylinder

30 flushing gas line

31 arrow

32 high voltage generation

33 stretching die tip

34 steel tube

35 holder

36 cable

37 moveable valve body

38 sealing seat

39 internal channel

40 pneumatic connector

41 fluid arrow

42 H₂ arrow

43 arrow (gas mixture inlet)

44 star (ignition)

45 outlet

46 ball

47 sealing seat in the hollow piston

48 sealing seat in the hollow piston

49 shoulder

What is claimed is:
 1. Device for manufacturing container (1, 1′) from aplastics material which can be formed by stretch-blowing with a mould,the internal space of which corresponds to the finished container (1),which is held by its open end (7) by a receiving portion (4), whereinlines (9, 10) connected to a metering unit are provided on the receivingportion (4), a moveable stretching die (11) is guided axially throughthe receiving portion (4) and an ignition means (12) is arranged inorder to ignite an explosive gas mixture inside the container (1′), andwherein heating and cooling means are provided, characterised in thatthe receiving portion (4), at its end opposite the container (1) can beengaged in a flowable medium-tight manner with a distributor module(14), through which the stretching die (11) is moveably passed axiallyextending the receiving portion (4), and on which at least one connectorfor flowable media (9, 10, 21) is fitted, in that the at least oneconnector for flowable media (9, 10, 21) can be closed off in order toseal the device-side interior space (22), and in that the ignition means(12) is fitted in the device-side interior space (22).
 2. A device forforming a deformable plastic material blank (2), having an open end (7),into a mold having an internal space shaped to correspond to a desiredshape of a container (1); said device comprising: a receiving portion(4) for holding and sealing to said open end (7), said receiving portionhaving a receiving portion axial channel for accommodating a movablestretching die (11); a distributor module (14) having a module axialchannel for accommodating a movable stretching die (11), saiddistributor module (14) engaging the receiving portion (4) in a fluidtight seal so that the receiving portion axial channel and module axialchannel are axially aligned and so that the distributor module andreceiving portion together have a device-side interior space (22), saiddistributor module further having at least one connector for at leastone fluid line to connect the fluid line to the device-side interiorspace; a movable stretching die (11) arranged to be guided axiallythrough the receiving portion axial channel and the module axialchannel; a metering unit; at least one tubular line connected betweenthe metering unit and said at least one connector of the distributormodule, said tubular line being closable to seal the device-sideinterior space; a heating means for heating the blank (2) to render itreadily deformable; an ignitor (12) positioned within the device-sideinterior space for igniting an explosive gas mixture within the blank(2); and a cooling means for cooling the finished container.
 3. A deviceaccording to claim 2 wherein the receiving portion (4) has, at an endopposite the container (1), an annular sealing surface (19) throughwhich the stretching die (11) is movably passed, axially extending thereceiving portion (4).
 4. A device according to claim 2 wherein theclosing means for sealing off the device-side interior space (22) is acheck valve (23).
 5. A device according to claim 2 wherein thestretching die (11) is hollow and has at least one outlet aperture (20)arranged on a stretching die tip, at least one fluid inlet (21) and atleast one internal channel (39) connecting aperture (20) and inlet (21).6. A device for forming a deformable plastic material blank (2), havingan open end (7), into a mold having an internal space shaped tocorrespond to a desired shape of a container (1); said devicecomprising: a receiving portion (4) for holding and sealing to said openend (7), said receiving portion having a receiving portion axial channelfor accommodating a movable stretching die (11); a distributor module(14) having a module axial channel for accommodating a movablestretching die (11), said distributor module (14) engaging the receivingportion (4) in a fluid tight seal so that the receiving portion axialchannel and module axial channel are axially aligned and so that thedistributor module and receiving portion together have a device-sideinterior space (22), said distributor module further having at least oneconnector for at least one fluid line to connect the fluid line to thedevice-side interior space; a movable stretching die (11) arranged to beguided axially through the receiving portion axial channel and themodule axial channel; a metering unit; at least one tubular lineconnected between the metering unit and said at least one connector ofthe distributor module, said tubular line being closable to seal thedevice-side interior space; a heating means for heating the blank (2) torender it readily deformable; an ignitor (12) positioned within thedevice-side interior space for igniting an explosive gas mixture withinthe blank (2); and a cooling means for cooling the finished container,wherein the stretching die (11) is hollow and has at least one outletaperture (20) arranged on a stretching die tip, at least one fluid inlet(21) and at least one internal channel (39) connecting aperture (20) andinlet (21); and wherein a check valve (23) is located within stretchingdie (11) proximate outlet aperture (20).
 7. A device according to claim6 wherein the ignitor (12) is fitted in the hollow stretching die (11)between check valve (230 and outlet aperture (20) and is oriented tostop flow from the aperture (20) to inlet (21) and the ignitor iselectrically connected by means of a cable (36) running in the hollowstretching die (11) to a control unit.
 8. A device according to claim 2wherein the stretching die (11) is a steel tube (34) with a cap-shapedstretching die tip on which the fluid outlet (20) is fitted in a holeand the check valve (23) is provided with a valve body (37) movable withrespect to a sealing seat (38) fitted inside the steel tube (34).
 9. Adevice according to claim 2 wherein a means is provided for movingreceiving portion (4) perpendicular to its longitudinal axis (13).
 10. Adevice according to claim 2 wherein the receiving portion (4) is widenedat an end opposite distributor module (14) to form a service space (5)in which a centering ring (6) is fitted.
 11. A device according to claim2 wherein an axially movable hollow piston (17) is arranged in thedistributor module (14), said piston being provided with an annularopposing sealing surface (18) fitting a sealing surface (19) of thereceiving portion (4).
 12. A device according to claim 11 wherein a seal(16) is fitted into a base of the distributor module (14) around thepiston ((17).
 13. A device according to claim 2 wherein at least onesupply line and at least one drainage line, connected to the meteringunit, are connected to the distributor module (14).
 14. A deviceaccording to claim 2 wherein each of the supply lines and drainage linesare connected to the distributor module (14) are connected to a checkvalve (23), and the ignition means (12) is fitted in the distributormodule (14).
 15. A device for forming a deformable plastic materialblank (2), having an open end (7), into a mold having an internal spaceshaped to correspond to a desired shape of a container (1); said devicecomprising: a receiving portion (4) for holding and sealing to said openend (7), said receiving portion having a receiving portion axial channelfor accommodating a movable stretching die (11); a distributor module(14) having a module axial channel for accommodating a movablestretching die (11), said distributor module (14) engaging the receivingportion (4) in a fluid tight seal so that the receiving portion axialchannel and module axial channel are axially aligned and so that thedistributor module and receiving portion together have a device-sideinterior space (22), said distributor module further having at least oneconnector for at least one fluid line to connect the fluid line to thedevice-side interior space; a movable stretching die (11) arranged to beguided axially through the receiving portion axial channel and themodule axial channel; a metering unit; at least one tubular lineconnected between the metering unit and said at least one connector ofthe distributor module, said tubular line being closable to seal thedevice-side interior space; a heating means for heating the blank (2) torender it readily deformable; an ignitor (12) positioned within thedevice-side interior space for igniting an explosive gas mixture withinthe blank (2); and a cooling means for cooling the finished containerwherein a hollow piston (17) is provided with an annular seat (47, 48)on an end facing the receiving portion (4), and the stretching die (11)carries a radially widened portion (46) perpendicular to itslongitudinal axis (13) on an end movable into the container to bemanufactured for engagement with the sealing seat.